The present invention relates to electrostatic transducers and more particularly to a method of making stationary electrodes for use in such transducers.
In the making of electrostatic transducers, e.g. high fidelity tweeters, an ongoing area of concern has been the fabrication of satisfactory stationary electrodes. In typical transducer arrangements, a pair of stationary electrodes are employed, one on either side of a diaphragmatic movable electrode. In order to obtain the greatest efficiency, the spacing between the movable electrode and the stationary electrode should be as small as possible and yet electrical breakdown between the electrodes should be prevented. These considerations indicate that the operative portion of the stationary electrode should be as flat as possible and should be insulated by a dieletric layer which is as thin as possible. As is understood, the stationary electrode should also offer substantial acoustic transparency so as to permit the radiation of acoustic energy generated by the movable electrodes. Prior approaches to constructing a stationary electrode are represented in my earlier U.S. Pat. Nos. 2,631,196, 2,896,025 and 3,800,102. In each of these arrangements, insulated wires were formed into flat, accoustically transparent structures and supported so as to constitute the stationary electrodes in an electrostatic transducer. While providing satisfactory constructions, each of these techniques involve relatively complex fabrication or delicate fabrication techniques.
Among the several objects of the present invention may be noted the provision of a method for making stationary electrodes which is adapted to relatively simple and inexpensive manufacturing techniques; the provision of such a method which produces electrodes whose active portions possess a high degree of flatness and can therefore be mounted in close proximity to movable electrodes; the provision of such a method which provides a high degree of dielectric protection for the active portions of the stationary electrodes so that breakdowns are eliminated; and the provision of such a method which is relatively simple and inexpensive. Other objects and features will be in part apparent and in part pointed out hereinafter.